A stator of the above general type is described in EP 0 993 095 A1/B1. With this known stator, the laminated stator core has an insulating plastic compound injected around it at both of its end sides and within stator slots, through which the stator winding is wound, the plastic compound forming an end insulation on both sides - in this case “insulating end disks”. A receptacle which is integrally formed on the end disk is provided on one side, and a temperature monitor is inserted axially into said receptacle. The temperature monitor, as a fuse element, is connected electrically in series upstream of the stator winding. In order to connect winding wires and connecting wires of the temperature monitor, a connecting arrangement having at least one multiple-contact chamber is provided which is formed by sub chambers on one of the end disks and on an additional wiring plate which is on the end-winding side. Contact elements in the form of insulation displacement contacts are arranged in the contact chambers. The wiring plate has a through-opening in the region of the temperature monitor and has fixing elements on its upper side for the purpose of holding the connecting wires of the temperature monitor in a clamping manner. The known stator is manufactured and mounted by the winding wire ends being guided through in each case one of the contact chambers and by contact being made there with the winding wire ends by insulation displacement contacts being inserted. It is then possible for connecting lines to be pushed into the respective contacts. The temperature monitor is inserted axially into the receptacle of the end disk, and its connecting wires are guided via the wiring plate and fixed there, and the ends of these connecting wires are inserted into corresponding insulation displacement contacts and, as a result, contact is made with said connecting wires.
EP 0 727 864 B1 describes a connecting arrangement for an electric motor, in which connector elements are held on a disk-shaped base part and have in each case one connection lug having a clamping tongue for the respective wire end for the purpose of connecting the stator winding wire ends. In this case, a special accommodating and contact-making arrangement is provided for a button-like temperature monitor which is in the form of a button battery without any connecting lines, this arrangement making it possible to assemble the motor either with or without a temperature monitor. For this purpose, the base part has a receptacle for the temperature monitor with a special contact spring element, by means of which it is possible to make contact either with the temperature monitor inserted into the receptacle or with a connector element to be used in place of the temperature monitor. A hole opening is formed in a bottom wall of the receptacle such that the temperature monitor resting in the receptacle is exposed to the heat of the stator winding through the hole opening, to be precise only indirectly via a contact section of a connector element and possibly via an additional circuit insulation. Thermal transfer is therefore not optimal.
The present invention is based on the object of providing a stator of the type described at the outset which ensures a high degree of reliability in use, with simplified manufacture and assembly.
According to the invention, the temperature monitor is thus held in an integrated manner in an insulating switching disk, which covers, in particular covers in the form of a cap, the region of the end winding such that, on the end-winding side, it rests between the stator winding and the switching disk such that it is in thermally conductive bearing contact with the stator winding. This means that the temperature monitor—preferably together with further contact elements of the connecting arrangement—is held in an integrated manner in the switching disk in preassembled form such that only the switching disk which has been provided in advance in this manner needs to be placed axially onto the wound laminated stator core. In this case, the temperature monitor bears, in direct bearing contact, against the stator winding on the end-winding side, which ensures effective heat transfer and, as a result, a high degree of reliability owing to the fact that the temperature monitor reliably disconnects the motor in the event of overheating.
In one advantageous refinement, the temperature monitor is fixed in the switching disk by means of its connecting wires, for which purpose the switching disk has fixing elements on its stator side facing the end winding for the purpose of accommodating and holding, in a clamping manner, the connecting wires. In addition, a spring-elastic pressure force is preferably applied to the temperature monitor, for which purpose the switching disk has a spring arm, which produces the pressure force, in the region of the temperature monitor. Owing to this advantageous refinement, tolerance compensation is achieved by any dimensional tolerances; in particular tolerances of the installation height of the end winding, being compensated for by the spring-loading of the temperature monitor such that, in any event, effective, direct thermal contact between the temperature monitor and the stator winding is ensured.
In one further preferred refinement, the connecting wires of the temperature monitor are connected directly using insulation displacement technology. For this purpose, the connecting wires are fixed in the switching disk such that contact is made with them automatically in insulation displacement contacts by means of a simple joint connection by the switching disk being placed axially onto the region of the end winding. This results in simple assembly of the stator.
Further advantageous design features will be explained in more detail below.